1. Field of the Invention
This invention relates to a strain relief for an electric appliance, the strain relief being a three-part molded plastic assembly accommodating any size conductors and in which various parts perform multiple functions.
2. Description of the Prior Art
Many portable cord connected electric appliances have stringent safety requirements. Generally, the requirements are such that the appliance should be supportable by the cord alone without putting undue strain on the internal electrical connections for the conductors within the cord. It is undesirable to transmit stress through the cord to the appliance terminals for obvious reasons and it is common to provide various forms of strain relef such as knots, wedges, clamps, or various plates to permit slack in the conductors in the appliance to thus relieve stress on the terminals. Also, to qualify for Underwriters' Labs Inc. approval other parameters must be met. Similarly, there are various foreign equivalents to U.L. that have their own requirements in order for the appliance to be acceptable. While cords and requirements vary, depending on the appliance, a typical appliance to subject the cord to stringent conditions is the electric flatiron and it is to this that the invention is directed for purposes of description although it is by no means so limited. A late development of cord used on appliances is heater parallel neoprene or HPN heater cord which involves chlorosulphonated polyethylene which has a very tough coating and is temperature resistant. Such a cord connecting structure is fully described in U.S. Pat. No. 3,665,374 of common assignment directed to means to prevent breaking of the fine wires within the conductors. In a flatiron, it is customary to provide a point where the cord is tightly compressed between two parts, generally in the iron handle or rear housing. Usually the conductors are attached to the internal terminals and laid against the handle and held by a coverplate with a sharp-edged tongue that presses or "bites" into the cord as the cover is tightened into the handle housing. This squeezing of the cord between the parts relieves the terminals of stress applied by the cord as shown at tongue 22 in said '374 Patent. Other forms of stress relief use clamps 39 as in U.S. Pat. No. 2,727,322 or a strain relief plate 74 in U.S. Pat. No. 2,602,248 both of common assignment. These are all extra parts individually manufactured that require manual labor to apply and so are more costly. An improved and simplified three-part molded plastic construction is desired that is useable with all cords and still meets the U.L. requirements.